Liquid charging method

ABSTRACT

A liquid charging method including the following steps. First, supplying liquid into and then discharging the liquid from an enclosed space provided above a pit block, to fill the liquid into a plurality of pits on the upper surface of the pit block. Each of the pits open at the upper surface of the pit block and have a small-diameter nozzle formed at the bottom of the pit block. Second, a tray having an array of containers with open upper ends is fed to be positioned below the pit block at a specified liquid-charged position. Pressurized air is supplied into the enclosed space to apply pressure on the liquid in the pits, thereby forcing the liquid in the pits to flow through the small-diameter nozzles into the array of containers on the tray.

This is a division of application Ser. No. 07/554,780, filed Jul. 20,1990, now U.S. Pat. No. 5,065,800.

BACKGROUND OF THE INVENTION

The present invention relates to a variable-capacity liquid chargingmethod and apparatus and more specifically to a method and an apparatusfor charging a specified amount of liquid into open containers, whichare empty capsules before being sealed with liquid in the process ofmaking liquid-filled capsules.

In recent years, an ever-increasing variety of tobacco products arecoming into market and, in the field of cigarette filters also, variouskinds of filter products are being proposed.

For example, there is a cigarette filter loaded with a small capsulewhich, during smoking, is broken by pressure to let liquid in thecapsule seep into the filter.

In such a filter, the liquid in the capsule may include water, perfumeor other substances to improve taste and smell of the tobacco. Bychanging the liquid contents, it is possible to provide cigarettes witha variety of tastes meeting a growing diversity of consumers' needs.

A common method of making such filters involves filling the liquid intoa container or capsule with one end open and hermetically sealing theopening with a lid.

A conventional technique for charging the liquid into the containerconsists in: installing the container with its opening facing up in abottomed recess formed in the upper surface of a tray; positioning thetray at a specified location; and loading into the container a specifiedamount of liquid by a plunger pump which is located above the tray andcan change its stroke to adjust the amount of liquid to be charged.

Such a liquid charging facility, however, has a very low efficiency asonly one container is charged with liquid during each stroke of thepump. Therefore, to fill a large number of containers at a time requiresarranging many pumps in parallel, which in turn increases not only thecost of the liquid charging equipment but also the design complexity,making the maintenance difficult.

SUMMARY OF THE INVENTION

This invention has been accomplished to solve the above-mentionedproblems and to provide a method and an apparatus that make it possibleto continuously charge a certain amount of liquid into small containerswith very high efficiency by using a simple facility.

To achieve the above objective, a liquid charging method according tothis invention comprises the steps of: supplying liquid into and thendischarging it from an enclosed space formed above a pit block andaround the outer circumference thereof so as to fill the liquid in aplurality of recesses or pits formed in the upper surface of the pitblock, each of said pits opening at the upper surface of the pit block,said pits each having a specified liquid accommodating volume and also asmall-diameter nozzle formed at the bottom thereof that pierces throughthe pit block; feeding a tray, on which an array of containers withtheir upper ends opened are installed; stopping and positioning saidtray below the pit block at a specified liquid-charging position;closing the valve on the exhaust piping to hermetically isolate theenclosed space; supplying pressurized air into the enclosed space toapply pressure on the liquid in the pits and thereby force the liquid inthe pits to flow down the small-diameter nozzles into the containers onthe tray; and carrying the tray from below the pit block.

A liquid charging apparatus that realizes the above method comprises: atray having an array of container accommodating recesses arranged atspecified pitches for accommodating containers with their upper endsopened; a stop device for stopping said tray carried on a conveyor at aliquid-charging position; a pit block having an array of pits andsmall-diameter nozzles, both formed therein and arranged above thecorresponding container accommodating recesses in the tray located atthe liquid-charging position, said pits opening at the upper surface ofthe pit block, said small-diameter nozzles each extending downwardlyfrom the bottom of each pit and opening a the underside of the pitblock; a frame enclosing the outer circumference of the pit block toform a liquid accommodating portion between the frame and the pit block;liquid guide grooves formed in the upper surface of the pit block forcommunicating each of the pits with the liquid accommodating portion; acover mounted on the upper edge of the frame to form a hermeticallyenclosed space inside the frame; a pressurized air piping forcommunicating the enclosed space with a pressurized air source through avalve; an exhaust piping for communicating the enclosed space with theopen air through a valve; a liquid supply piping for communicating theliquid accommodating portion with a liquid tank through a supply pump;and a liquid discharge piping for communicating the liquid accommodatingportion with the liquid tank; whereby a pressure is applied to theliquid in the pits to force the liquid to be charged into the containerson the tray at the liquid-charging position.

In order to prevent the liquid in the pits from falling down from thenozzles, the enclosed space formed above the pit block and around theouter circumference thereof is preferably depressurized by a vacuumsource through a piping connecting the space with the vacuum source.

To adjust the amount of liquid accommodated in each pit, needles areprovided in the cover in such a way that their positions can be adjustedand their front ends protrude into the pits.

The liquid guiding grooves may consist of a plurality of parallellyarranged communication grooves and a plurality of parallelly arrangedthrough-grooves intersecting the communicating grooves, these two kindsof grooves being formed in the upper surface of the pit block. On thesurface of the pit block where the array of pits are arranged in rowsand columns, the communication grooves run between columns of pits andcommunicate at the ends with the liquid accommodating portion. Thethrough-grooves are made to cross the communicating grooves, rundirectly through the rows of pits, and have their bottoms set higherthan those of the communication grooves. The liquid guiding grooves mayalso be formed as either rows or columns of grooves which run betweenthe adjacent rows or columns of the pits in such a manner as to cut apart of the upper portion of each pit.

With the above liquid charging method and apparatus, the liquid ischarged into containers as follows.

The enclosed space is formed above the pit block and around its outercircumference, and defined by the cover and the frame. First, the supplypump is started to supply the liquid from the liquid tank through theliquid supply piping to the space. This causes the liquid to bedelivered into the space until the liquid level rises to a certainlevel, higher than the top open ends of the pits.

Then, the liquid in the space is discharged through the liquid dischargepiping. As a result, the pits, each of which has a specified amount ofvolume, are filled with the liquid.

The pits each have a nozzle which extends downwardly through the pitblock and opens at the underside thereof. Since the nozzle diameter isvery small, the liquid does not flow and get discharged from thenozzles. As mentioned above, depressurizing the space before supplyingliquid into the space prevents with more certainty the liquid fromflowing down.

When the tray carried on the conveyor is stopped at a specifiedposition, the array of containers on the tray are positioned immediatelybelow the corresponding nozzles.

When the valve on the exhaust piping is closed, the liquid accommodatingportion is hermetically isolated. As the air pressure is supplied to theenclosed space through the pressurized air piping, the liquid in thepits are pressurized to flow down the narrow nozzles out into thecontainers below, filling each of the containers with a specified amountof liquid. The tray is then moved out of the liquid-charging position,thus completing one cycle of liquid charging process.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 through 4 illustrate embodiments of the invention; of which

FIG. 1 is an elevational cross section of a liquid charging apparatusaccording to the invention;

FIG. 2 is a plan view of a pit block;

FIG. 3 is a partial plan view of other embodiment of the pit block; and

FIG. 4 is a partial, elevational side view as seen from arrow X of FIG.3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the invention will be described by referring tothe accompanying drawings.

In FIG. 1 showing the vertical cross section of the liquid chargingapparatus, a frame 1 consists of a bottom wall 1b with an opening 1aformed at the center, a side wall 1c rising from the periphery of thebottom wall 1b, and a flange portion 1d bent and extending radiallyoutward from the upper edge of the side wall 1c.

The bottom wall 1b is provided with a seal groove 2 running parallelwith the opening 1a. The seal groove 2 is fitted with a sealing material3 such as O-ring to make water-tight the contact portion between thebottom wall 1b and a pit block 4 assembled onto the bottom wall 1b. Onthe outer circumference of the pit block 4 there is formed a liquidaccommodating portion 5 which is enclosed by the bottom wall 1b and theside wall 1c.

The pit block 4 has an array of upwardly opening circular pits 6 formedtherein, which are equidistantly arranged in two orthogonal directions,twelve pits along a longitudinal side (in the widthwise direction inFIGS. 1 and 2) and twelve pits along a lateral side (in the direction ofarrow H in FIG. 2).

At the bottom of each pit 6 is formed a narrow nozzle 7 that passesthrough the pit block 4 and opens at the underside thereof. Since thediameter of the nozzles 7 is very small, liquid such as water fillingthe pits 6 is prevented from flowing out of the nozzles 7 by the surfacetension of the liquid. A groove is formed around the lower end of eachnozzle 7.

On the upper side of the flange portion 1d of the frame 1 is formed acircular seal groove 8, into which a sealing material 9 is installed tokeep air-tight the contact part between the frame 1 and a cover 10mounted on the frame 1. Thus, a hermetically enclosed space is formedinside the frame 1.

The cover 10 is formed with threaded holes 11 at positions aligned withthose of the corresponding pits 6. Into each threaded hole 11 is screweda needle 12 that has a male thread 12a cut on its outer circumferentialsurface.

The needle 12 has a conically pointed front end 12b and at the rear endis engraved with a tool accommodating groove 12c to allow fineadjustment of the position of the front end 12b of the needle 12protruding into the pit 6 by turning a tool like screwdriver engaged inthe groove 12c.

While in this embodiment the screw is used in finely adjusting theposition of the needle 12, it is also possible to use a frictionmechanism.

On the upper side of the pit block 4 there are formed two groups ofgrooves perpendicularly crossing each other. One group is communicationgrooves 13 that run between the columns of pits 6 to reach the both endsof the pit block 4. The other group is through-grooves 14 that intersectthe communication grooves 13 at right angles and extend directly throughthe rows of pits 6 to reach the both ends of the pit block 4. Thecommunication grooves 13 and the through-grooves 14 constitute liquidguide grooves 15 that keep each pit 6 in communication with the liquidaccommodating portion 5. (See FIG. 2.)

The bottoms of the through-grooves 14 are shallower than those of thecommunicating grooves 13 (see FIG. 1), so that as the liquid level inthe liquid accommodating portion 5 rises, the liquid enters thecommunication grooves 13 first and then the through-grooves 14, fromwhich it flows into the pits 6.

The side wall 1c, which constitutes the inner wall of the liquidaccommodating portion 5, is provided with an upper limit detector 16 todetect the upper limit of the liquid level and with a lower limitdetector 17 for the lower limit of the liquid level. The cover 10receives a pressurized air piping 18 that opens into the liquidaccommodating portion 5.

The pressurized air piping 18 communicates with a pressurized air source23 through a filter 19, a valve 20, a pressure regulating valve 21 and afilter 22.

The valve 20 in this embodiment is a solenoid valve, but may be of atype that is operated manually or by air pressure to open or close thepressurized air piping. While in this embodiment a pressure tank is usedas the pressurized air source 23, a compressor may be used instead.

The pressurized air piping 18 has branches 18a and 18b, to each of whichis attached a pressure gauge 24, 25.

The cover 10 is also provided with a vacuum piping 52 that opens intothe liquid accommodating portion 5. Vacuum piping 52 has a branch 52awhich is attached to a pressure gauge 54. The vacuum piping 52 isconnected to a vacuum source 50 via a filter 53 and a valve 51. Thevacuum source 50 in this embodiment is a vacuum tank but may use avacuum pump instead. This embodiment employs a solenoid valve for thevalve 51, whereas a manually or pneumatically operated valve can also beused in opening or closing the vacuum piping.

The cover 10 is also fitted with an exhaust piping 26 which opens intothe liquid accommodating portion 5 and communicates through a filter 27with a valve 28 that opens into the external atmosphere. The valve 28 isa solenoid valve in this embodiment but may be other type of valve, asin the case of the valve 20.

The side wall 1c is provided with a liquid supply piping 29 opening intothe liquid accommodating portion 5; it also receives a liquid dischargepiping 30 opening into the liquid accommodating portion 5 at a positionbelow the lower limit detector 17. The liquid supply piping 29communicates with a liquid tank 32 through a supply pump 31. The liquiddischarge piping 30 also communicates with the liquid tank 32 through adischarge pump 33.

The liquid in the tank 32 is replenished by a delivery pump 36 on aliquid delivery piping 35 that connects a large liquid reservoir 34 andthe liquid tank 32.

The liquid tank 32 is provided at the top with a pipe 38 thatcommunicates through a filter 37 with the open air; the liquid reservoir34 is provided at the top with a pipe 40 that opens through a filter 39into the open air. These pipes ensures that the interiors of the liquidtank 32 and the liquid reservoir 34 are kept at the atmosphericpressure.

Installed below the pit block 4 is a conveyor 41 of roller type, belowwhich is further installed a stop device 44 which consists of a cylinder42, a cylinder rod 42a, and a stopper 43 fixed at the end of the rod42a. As the rod 42a is raised, the stopper 43 projects above theconveyor 41 to stop a material being carried at a specified position.The cylinder may be replaced with a solenoid for raising or lowering thestopper 43.

Immediately above the conveyor 41 is provided a detector 45, whichdetects a tray 46 being carried on the conveyor 41 in the direction ofarrow F, at which time the stopper 43 is projected from the uppersurface of the conveyor 41 stopping the tray 46 at a predeterminedposition below the pit block 4.

The widthwise position of the tray 46 (in a direction normal to theplane of the sheet of FIG. 1) is determined by guides (not shown)mounted on both sides of the conveyor. The tray 46 has a plurality ofrecessed portions 47 arranged in the same pitch and pattern as those ofthe pits 6. The recessed portions each accommodate a container orcapsule 48 with the upper end opened. When the tray 46 is stopped andpositioned at a specified location, the containers 48 are positionedimmediately below the corresponding nozzles 7.

Now, the process of charging liquid into the containers by using theliquid charging apparatus with the above-mentioned construction will beexplained.

Preparation

With the discharge pump 33 stopped, the valves 20 and 28 closed, and thevalve 51 open, the supply pump 31 is started. This causes the liquid inthe liquid tank 32 to flow through the liquid supply piping 29 into theliquid accommodating portion 5. And the liquid accommodating portion 5is depressurized.

When the liquid level in the liquid accommodating portion 5 becomeshigher than the communication grooves 13, the liquid flows into thecommunication grooves 13. Then as the liquid level moves further up andbecomes higher than the through-grooves 14, the liquid enters from thecommunication grooves 13 into the through-grooves 14 and then into eachof the pits 6 through two side openings at the upper part of each pitthat communicate with the through-grooves 14. As the liquid pours intothe pits 6, the air in the pits 6 is smoothly expelled through otherthan the side openings.

In this way, the residual air is not hindered from escaping by theliquid flowing into the pits 6 and therefore it is not trapped in thepits 6 as bubbles. In other words, even when the liquid inflow is fast,the specified amount of liquid can reliably be poured into the pits 6 atall times.

The liquid supplied into the pits 6 does not fall from the nozzles 7because of the small diameter of the nozzle 7 and the surface tension ofliquid and because the liquid accommodating portion 5 is depressurized.

When the level in the liquid accommodating portion 5 rises to the upperlimit detector 16, the detector outputs a liquid detection signal tostop the supply pump 31 and start the discharge pump 33, followed by thevalve 28 being opened and the valve 51 being closed to bring the liquidaccommodating portion 5 into communication with the open air. The liquidis then returned to the liquid tank 32 through the liquid dischargepiping 30.

When the liquid level goes down below the through-grooves 14, the liquidin the pits 6 is at the same level as the bottom of the through-grooves14, retaining a specified amount of liquid in each pit 6. Under thiscondition, the liquid in the pits is stationary and its level low, sothat it does not fall by gravity from the nozzles 7. In the case ofwater, for example, if the nozzle diameter is 0.5 mm, the water will notflow down the nozzle by gravity until the water column in the pit 6 ismore than 30 mm high.

The amount of liquid received in the pit 6 can be finely adjusted withease by engaging the tip of a screwdriver in the tool accommodatinggroove 12c of the needle 12 and turning it in either direction.

When the lower limit detector 17 detects the lowering liquid level inthe liquid accommodating portion 5, the discharge pump 3 is stopped andthe valve 28 closed. With the above steps taken, the preparation stageis now complete.

Charging Liquid

When the tray 46 being carried on the conveyor 41 in the direction ofarrow F comes under the pit block 4, the detector 45 senses theapproaching front end of the tray 46, causing the stopper 43 of the stopdevice 44 to move up.

As the front end of the tray 46 contacts the stopper 43, the containers48 installed in the recessed portions 47 of the tray 46 are positionedimmediately below the corresponding nozzles 7. At the same time thevalve 20 is opened to supply the pressurized air from the pressurizedair source 23 through the piping 18 into the hermetically enclosed spaceor the liquid accommodating portion 5. The air pressure supplied causesa predetermined amount of liquid in each of the pits 6 to fall out ofthe nozzles 7 into the corresponding containers 48 below. The grooveformed around the bottom outlet of the nozzle prevents the liquid, whenit drops, from spreading over the underside of the pit block 4 andfalling onto undesired parts of the tray. This ensures that the preciseamount of liquid can reliably be supplied into each of the containers48.

With the containers filled with the liquid, the stopper 43 of the stopdevice 44 is lowered and the tray 46 is again moved in the direction ofarrow F on the conveyor 41 to the next process, where the openings inthe containers are sealed to form the liquid-filled capsules.

After a specified period of time, the valve 20 is closed to stop afurther supply of pressure and the valve 51 is opened to depressurizethe hermetically enclosed space. At the same time the supply pump 31 isstarted to load liquid into the pits 6 in a way similar to that in whichthe above-mentioned preparation process was carried out.

Now, one cycle of liquid charging process is complete and this processis repeated in the same manner, continuously charging the predeterminedamounts of liquid into a large number of containers with highefficiency.

This kind of liquid charging in small containers can be applied not onlyto tobaccos but also to liquid seasonings, perfumes, and drugs.

FIGS. 3 and 4 show another embodiment of the liquid guide grooves 15formed in the surface of the pit block 4. FIG. 3 is a plan view of theessential portion of the pit block and FIG. 4 is a partial cross sectionof the same as seen from arrow X in FIG. 3. In this embodiment, liquidguide grooves 49 are provided between the rows of pits 6 in such a waythat they cut a part of the upper circumferential portion of the pits 6.

The bottom of the liquid guide grooves 49 is equal in height to thebottom of the through-grooves 14 of the first embodiment. The liquidflowing from the guide grooves 49 into the pits enters through the uppertwo cut openings of each pit, so that the air in the pits can safelyescape from other than the cut openings as in the first embodiment,without any residual air being trapped in the pits as bubbles.

Advantages of the Invention

The advantages of the invention may be summarized as follows:

(1) In the liquid charging method and apparatus of this invention,narrow nozzles, which do not let liquid fall through under theatmospheric pressure, are provided to the bottom of the pits, each ofwhich has a specified liquid receiving capacity. By applying pressure tothe liquid in the pits, it is possible to deliver a certain amount ofliquid into a plurality of containers arranged below at once. Thus,liquid charging into a plurality of containers can be done efficientlyin a very short time.

The application of the liquid charging method and apparatus of theinvention is not limited to the field of tobacco. It can also be appliedto other technical fields involving the process of charging liquid intosmall containers. For example, it may be utilized in the process ofcharging liquid seasonings, perfumes and drugs into small capsules.

(2) Since the pits are replenished with liquid after the liquid wasdriven out of the pits through the nozzles, the liquid charging into thecontainers can be performed repetitively and continuously.

(3) Since the needles with their front ends inserted into thecorresponding pits can easily be adjusted in position, it is very easyto finely adjust the amount of liquid loaded in each pit.

(4) In place of a plunger pump which is complex in construction, pitseach attached with a nozzle at the bottom are used. This construction issimple and has high durability, reducing the probability of failure andmaking inspection and maintenance easier. This construction also makesthe cost of manufacture lower than that of the conventional liquidcharging apparatuses.

(5) Since the liquid guide grooves are formed so as to cut a part of theupper portion of each pit, the liquid flowing into the pit does nothinder the air from escaping from the pit, so that there is nopossibility of any residual air bubbles being formed which would reducethe amount of liquid supplied to the pit.

What is claimed is:
 1. A liquid charging method comprising the stepsof:supplying liquid into and then discharging the liquid from anenclosed space formed above a pit block and around an outercircumference thereof to fill the liquid in a plurality of pits formedin an upper surface of the pit block, each of said plurality of pitsopening at the upper surface of the pit block, said plurality of pitseach having specified liquid accommodating volume and a small-diameternozzle formed at a bottom thereof that pierces through the pit block;feeding a tray, on which an array of containers with their upper endsopened are installed; stopping and positioning said tray below the pitblock at a specified liquid-charged position; supplying pressurized airinto the enclosed space to apply pressure on the liquid in the pluralityof pits and thereby force the liquid in the plurality of pits to flowdown the small-diameter nozzles into the array of containers on thetray; and carrying the tray from below the pit block.
 2. A liquidcharging method as claimed in claim 1, wherein said enclosed spaceformed above the pit block and around the outer circumference thereof isdepressurized before supplying liquid into the space.